Preejection sequencer for aircraft



March 16, 1965 W. H. SIMMONS PREEJECTION SEQUENCER FOR AIRCRAFT FiledJan. 5, 1964 INVENTOR. WILLIAM H. SIM MONS BY 777. 6 0/615 Mm J.

ATTORNEY United States Patent 3,173,635 PREEJECTION SEQUENCER FGRAIRCRAFT William H. Simmons, Houston, Tex., assignor to the UnitedStates of America as represented by the Secretary of the Army Filed Jan.3, 1964, Ser. No. 335,703 2 Claims. (Cl. 244-122) (Granted under Title35, US. Code (1.952), sec. 266) The invention described herein may bemanufactured and used by or for the Government for governmental purposeswithout the payment to me of any royalty thereon.

This invention relates to preejection apparatus for aircraft.

In such apparatus, a number of propellant actuated devices have to beoperated in sequence, close together in time and automatically. Thenumber of such devices may be too large for a crewman to operatemanually in the desired order under stress of necessity for haste andpossible danger. In event any propellant actuated device fails tofunction, then those devices dependent upon it for being later actuatedwill also fail to function. Manually operated initiators have been triedat critical locations but beside leaving much to human error, have anundesirable increase in weight.

An object of this invention has been to reduce the weight in this typeapparatus, enhance its reliability, simplify its construction andimprove its accuracy over an extended range of environmentaltemperatures.

According to this invention, this preejection apparatus has beensimplified and made lighter and made more reliable. Specifically, thefunctions of two gas pressure sources and the pyrotechnic delay trainhave been combined into a single device which replaces the first gaspressure source with the result that the preejection apparatus is notonly simplified but made about 12% lighter in weight and with asignificant gain in reliability. In addition, this inventonsignificantly improves the timing accuracy of the apparatus byeliminating the pyrotechnic delay train which is undesirably sensitiveto variations in environmental temperature.

Referring to the drawings:

FIG. 1 is a diagrammatic representation of the preejection apparatus ofthis invention including the sequencer of FIG. 2.

FIG. 2 shows a preferred embodiment of the sequencer of this invention.

Referring to FIG. 1, a solid propellant pressure type sequencer 11,shown also in FIG. 2, is connected by a gas pressure line 12 leading toa dump valve 15 for reducing cabin pressure to a safer level beforepersonnel are ejected in the customary manner in their seats. Anotherpressure line 13 from sequencer 11 leads to a canopy unlocking mechanism14 to be actuated after a usual predetermined time interval has elapsedsubsequent to actuation of the valve 15. The canopy jettison device 16is operated in the usual manner after the functioning of canopy unlockmechanism 14. In the event of failure of the mechanism 14 to actuatedevice 16, then to insure that the device will nevertheless function,another pressure line 17 leads from sequencer 11 to the device 16.

In FIG. 2, the sequencer of FIG. 1 includes a fluid pressure cylinder 24closed at one end by a pressure cap 8 and firing head 23 and containinga propellant charge or cartridge 9 and means familiar in the art foractuating said charge electrically, mechanically or pneumatically.Orifice is located at the end of said cylinder opposite pressure cap 8and is covered by a separable or frangible cover 18 to retain thecontrol fluid in cham- 3,ii3,635 Patented Mar. 16, 1965 her 25 until itsdischarge is desired. Fluid discharge control rod 26 is afiixed topiston 27 and extends through said orifice, thus restricting saidorifice to a desired area for fixing a basic maximum fluid dischargerate. When pressure generated by charge 9 has increased to a designedlevel in chamber 28 the cover 18 is removed or ruptured and said pistonand control rod move up-- ward with their velocity being controlled bythe dis= charge rate of the control fluid through said orifice. Pressurelines 29, 30 and 31 are sequentially uncovered at designated timeintervals to supply pressurized gas in a timed sequence to whatever theymay be connected in a manner corresponding to the pressure lines 12, 13and 17 in FIG. 1. Indentations or cuts 19 at appropriate locations inthe control rod 26 reduce the cross-sectional area of this rod andincrease the effective orifice area at times corresponding to theopening of successive pressure lines. Changeable orifice inserts may beprovided to permit ready variation of the basic fluid discharge ratethus permitting a single device to be used in difierent apparatus.Similarly, changeable control rods of suit-- able configuration may beprovided to permit the device to be adapted to varied sequentialprograms in different apparatus. O-ring 21 prevents fluid from chamber25 from entering the pressure lines and O-rin'g' 22 provents gas fromchamber 28 from prematurely entering the pressure lines. 7

To obtain a substantially uniform propellant burning rate is believedwithin the skill of the art. An alternate way of obtaining substantiallyuniform pressure, involves what is known as a high-low system whereinpropellant is supplied at any conventient rate to a high pressurechamber and metered into a lower pressure chamber at a substantiallyconstant rate. Any well known suitable type of primer or initiator maybe used for firing the propellant cartridge.

I claim: H

1. In an aircraft preejection apparatus including it source of gaspressure, means comprising a dump valve actuated by gas from said sourcefor dropping cabin pressure, a canopy unlocking means, a time delaydevice between said source and said canopy unlocking means whereby cabinpressure is dropped before the canopy is unlocked, means for jettisoningsaid canopy after it has been unlocked, the combination therewith of theimprovement for simplifying said apparatus and reduc-- ing its weight,said improvement including a corribinaton of said source of gas pressureand said time delay device into a single unit of sequencer type thrusterincluding a cylinder and piston therein, a propellant in said cylinder,a control rod connected to said piston and projecting out of an end wallof said cylinder, said rod having spaced portions of reduced diameterfor controlling a cushioning delay between said piston and a cylinderend wall through which said control rod extends, said cylinder beingprovided with a plurality of exhaust ports sequentially uncovered bysaid piston, a pressure line leading from a first exhaust port uncoveredby said piston and leading to said dump valve, and second pressure lineleading from a second exhaust port uncovered by said piston to saidcanopy unlocking means.

2. Apparatus according to claim 1 in which a third pressure line leadsfrom a third exhaust uncovered by said piston to said canopy jettisoningmeans.

References Cited by the Examiner UNITED STATES PATENTS 1,915,435 6/33Miller 891.01 2,370,526 2/45 Doran 6053 2,892,602 6/59 Servanty244.-122.

FERGUS S. MIDDLETON, Primary Examiner.v

1. IN AN AIRCRAFT PREEJECTION APPARATUS INCLUDING A SOURCE OF GASPRESSURE, MEANS COMPRISING A DUMP VALVE ACTUATED BY GAS FROM SAID SOURCEFOR DROPPING CABIN PRESSURE, A CANOPY UNLOCKING MEANS, A TIME DELAYDEVICE BETWEEN SID SOURCE AND SAID CANOPY UNLOCKING MEANS WHEREBY CABINPRESSURE IS DROPPED BEFORE THE CANOPY IS UNLOCKED, MEANS FOR JETTISONINGSAID CANOPY AFTER IT HAS BEEN UNLOCKED, THE COMBINATION THEREWITH OF THEIMPROVEMENT FOR SIMPLIFYING SAID APPARATUS AND REDUCING ITS WEIGHT, SAIDIMPROVEMENT INCLUDING A COMBINATION OF SAID SOURCE OF GAS PRESSURE ANDSAID TIME DELAY DEVICE INTO A SINGLE UNIT OF SEQUENCER TYPE THRUSTERINCLUDING A CYLINDER AND PISTON THEREIN, A PROPELLANT IN SAID CYLINDER,A CONTROL ROD CONNECTED TO SAID PISTON AND PROJECTING OUT OF AN END WALLOF SAID CYLINDE,R SAID ROD HAVING SPACED PORTIONS OF REDUCED DIAMETERFOR CONTROLLING A CUSHIONING DELAY BETWEEN SAID PISTON AND A CYLINDEREND WALL THROUGH WHICH SAID CONTROL ROD EXTENDS, SAID CYLINDER BEINGPROVIDED WITH A PLURALITY OF EXHAUST PORTS SEQUENTIALLY UNCOVERED BYSAID PISTON, A PRESSURE LINE LEADING FROM A FIRST EXHAUST PORT UNCOVEREDBY SAID PISTON AND LEADING TO SAID DUMP VALVE, AND SECOND PRESSURE LINELEADING FROM A SECOND EXHAUST PORT UNCOVERED BY SAID PISTON TO SAIDCANOPY UNLOCKING MEANS.